Monzo and Revolut, both fintech startups, have found themselves disrupted (Source: Monzo)

Lynsey Barber

Monzo cardholders are unable to use the digital challenger bank to make payments or send money and might not be able to for the rest of the day.

In a notification sent to customers, the startup said there have been issues since just before 10 am on Sunday morning due to one of its suppliers running "an unexpected large migration" with no estimate of when services will return.

The issue is also affecting Revolut, another fintech startup which issues cards to customers.

Both firms are advising customers to use another card and apologised for any inconvenience.

UPDATE: Due to our card processor server issue we advise you to keep another card with you for the rest of the day. We’ll keep you posted.